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UNIVERSITY  OF  ILLINOIS, 

Agricultural  Experiment  Station. 

CHAMPAIGN,  FEBRUARY,  1891. 


BULLETIN  NO.  14. 


MILK  TESTS:  METHODS  OF  TESTING  MILK. 

In  this  bulletin  matters  concerning  dairy  interests  are  treated  under 
the  following  heads: 

1.  In  continuation  of  the  work  published  in  bulletin  No.  10,  a  report 
is  given  of  tests  made  of  the  milk  of  50  cows  belonging  to  four  herds  in 
different  parts  of  the  state.     Also  a  record  of  the  tests  made  of  the  milk 
furnished  in  one  day  to  two  creameries,  one  having  48  patrons,  and  the 
other,  30  patrons  who  sell  their  milk  by  the  amount  of  butter  fat  it  con- 
tains, as  shown  by  test.   The  tests  all  show  that  there  is  great  variation  in 
the  value  of  cows  for  producing  butter,  and  demonstrate  the  usefulness  of 
an  accurate  "  milk  tester  "  by  which  any  intelligent  person  can  determine 
readily  the  butter  fat  in  milk,  skim-milk,  buttermilk,  or  cream. 

2.  A  description,  with  illustration,  of  a  method  of  taking  at  cream- 
eries samples  of  milk  for  test. 

3.  A   comparison   of    the   Patrick,   Babcock,    and   Beimling   "milk 
testers  "  with  each  other  and  with  gravimetric  laboratory  analyses,  when 
used  with  the  same  sample  of  milk. 

4.  A  description,  with  illustrations,  of  apparatus  designed  for  use  in 
measuring  the  acid  for  milk  tests  by  the  Babcock  method. 

5 .  Chemical  analyses  oigerm  meal  and  oat  dust  feed,  two  comparatively 
new  feeding  stuffs  which  some  claim  may  be  used  with  much  profit  in 
feeding  milch  cows  when  the  prices  of  corn  and  oats  are  as  high  as  now. 

Experiment  No.  106.     Milk  and  Butter  Tests. 

TESTS  OK  MILK  OF  SEPARATE  Cows,  AND  OF  MILK  AS  BROUGHT  BY  PATRONS 

TO  CREAMERIES. 

The  butter  fat  in  milk  is,  for  all  practical  purposes,  a  good  measure 
of  its  value.     It  is,  indeed,  only  one  of  the  constituents,  and  of  the  others 


454  BULLETIN  NO.  14.  [February, 

the  casein  is  of  greater  importance  to  the  cheese  maker,  while  the  protein 
substances,  as  well  as  the  milk  sugar  and  the  ash,  are  valuable  food.  But 
the  greatest  importance  must  be  ascribed  to  the  fat,  not  only  because  it 
supplies  us  with  butter  but  because  it  is  also  essential  for  the  best  cheese. 
It  may  also  be  accepted  as  a  general  rule  that  milk  rich  in  butter  fat  has 
a  proportionately  high  content  of  other  solids  not  fat. 

The  richer  milk  is  in  its  valuable  constituents  such  as  fat,  etc.,  the 
greater  are  the  receipts  from  the  productions  of  the  dairy,  provided  it 
does  not  cost  more  to  produce  the  rich  than  the  thin  milk.  Take,  for  ex- 
ample, two  cows  whose  value  and  maintenance  are  equal:  The  milk  from 
one  produces  125  Ib.  of  fat  from  which  125  Ib.  of  butter  can  be  made; 
the  other,  however,  under  the  same  conditions,  produces  150  Ib.  It  is 
plain  then  that  the  second  animal  is  worth  most  to  the  dairyman.  This 
fact  remains  unchanged  whether  the  smaller  quantity  of  125  Ib.  was  ob- 
tained from  3,000  Ib.  of  milk  with  4.17  per  cent,  of  fat,  from  4,000  Ib.  with 
3.12  per  cent,  or  from  5,000  Ib.  with  2.5  per  cent;  or  whether  the  larger 
yearly  amount  of  150  Ib.  was  obtained  from  3,000  Ib.  of  milk  with  5  per 
cent,  of  fat,  from  4,000  Ib.  with  3.75  per  cent.,  or  from  5,000  Ib.  with  3  per 
cent.  For  manufacturing  butter,  cheese,  or  condensed  milk  the  absolute 
quantity  of  solids,  especially  fat,  in  the  milk  becomes  of  the  first  import- 
ance. The  smaller  the  quantity  of  milk  in  which  a  certain  quantity  of  the 
valuable  constituents  is  contained;  or  in  other  words,  the  richer  the  milk, 
the  less  the  cost  of  manipulation.  An  endeavor  to  procure  milk  of  as  rich 
a  quality  as  possible  is  in  the  interest  of  higher  receipts  from  the  dairy. 

In  attempting  to  find  a  means  for  improving  the  quality  of  the  milk 
from  a  herd,  one  thing  necessary  to  do  is  carefully  to  inspect  each  cow. 
Not  all  cows  fed  and  kept  under  the  same  conditions  will  produce  the 
same  quantity  and  quality  of  milk.  They  are  not  machines  but  living 
creatures,  endowed  with  incalculable  peculiarities  and  innumerable  differ- 
ences. It  does  not  require  much  careful  thought  to  convince  one  that  the 
milk  formation  and  separation,  as  well  in  amount  as  in  richness,  is  meas- 
ured by  the  individual  capacity;  and  observation  repeatedly  teaches  that 
among  a  number  of  cows  fed  and  cared  for  in  exactly  the  same  way  cer- 
tain ones  may  be  found  which  furnish  milk  differing  extraordinarily  in 
composition.  The  money  value  and  profit  that  may  be  obtained  from  the 
so-called  testing  of  dairy  cows  is  so  obvious  that  an  explanatioa  seems 
hardly  necessary.  The  answer  to  the  question,  What  shall  we  do  in  order 
to  improve  the  composition  of  milk  ?  is  not  very  difficult.  First  of  all 
it  is  necessary  to  determine  quite  frequently  the  amount  of  fat  in  the  milk 
of  each  cow  in  a  herd.  The  more  tests  and  observations  there  are  made 
and  published,  the  more  firmly  established  will  be  the  foundation  for  any 
conclusions  drawn,  and  the  greater  will  be  the  zeal  for  further  improve- 
ment in  the  composition  of  milk.  To  be  sure,  some  veteran  experimenters 
among  dairymen  have  been  thinking  and  working  at  this  idea  for  a  long 
time,  and  testing  their  cows  by  churning  the  milk  of  each  one  separately; 
but  we  should  have  cause  for  a  great  deal  of  encouragement  if  the  number 


1891.]  MILK  TESTS:  METHODS  OF  TESTING  MILK.  455 

of  cows  whose  butter  value  had  been  tested  five  years  ago  were  compared 
with  the  much  larger  number  at  the  present  time  that  has  been  tested  by 
some  one  or  all  of  the  multitude  of  milk  tests  of  recent  origin. 

If  a  satisfactory  dairy  herd  has  been  obtained  by  regularly  testing 
the  cows  for  some  time,  the  next  problem  is  to  breed  calves  that  shall  have 
the  desired  qualities  of  the  mother  as  regards  quantity  and  composition  of 
milk.  Breeders'  associations  and  herd-book  societies  could  be  very  useful 
in  this  respect,  if  in  their  registers  of  milch  cows  they  would  include  state- 
ments giving  for  each  cow  the  amount  of  milk  produced  and  the  per  cent, 
of  fat  it  contained.  When  some  such  system  as  this  shall  have  been 
adopted  the  dairyman  will  be  in  a  better  position  to  control  many  of 
the  circumstances  which  now  control  him  in  a  large  measure. 

One  dairyman  may  be  conscious  that  the  butter  produced  by  his  herd 
is  a  little  too  soft,  though  it  has  a  high  flavor.  Another  one  may  produce 
butter  that  is  hard  and  solid  but  has  not  flavor  enough.  If  now  records 
were  kept  both  of  the  melting  point  of  the  butter  fat  of  each  cow  and  of 
the  amount  of  the  soluble  fatty  acid  which  gives  to  her  butter  its  flavor, 
might  not  the  one  dairyman  improve  the  texture  and  the  other  the  flavor 
of  his  dairy  output  by  adding  to  his  herd  cows  capable  of  making  such 
changes  therein,  or  by  removing  from  the  herd  the  cows  to  which  the  de- 
fects were  chargeable  ?  At  present  it  is  much  plainer  what  the  defect  is, 
than  what  the  cow  is;  we  need  a  more  intimate  knowledge  of  each  cow. 
Some  would  improve  on  acquaintance;  familiarity  with  others  would 
breed  contempt. 

Extensive  and  accurate  experiments  have  taught  us  some  of  the  pe- 
culiar ities  of  the  different  dairy  breeds,  and  as  a'  rule,  thoroughbred  stock 
can  be  depended  on  to  furnish  the  quantity  and  quality  of  milk  and  butter 
characteristic  of  its  breed;  but  there  are  exceptions  even  among  cows  of 
the  same  breed.  An  Experiment  Station  report*  gives  the  following  data 
in  regard  to  two  registered  cows  of  the  same  breed: 

Cow  No.  i.  Cow  No.  2. 

cts.  cts. 

Cost  of  milk  per  pound 8674  1.411 

milk  , per  quart.  .T 1.86  3.02 

solids  per  pound 5.87  9.08 

butter  fat  per  pound 16.94  24-39 

cream  per  pound 3-76  6.09 

cream  per  quart 8.06  13-°5 

butter  per  pound I5-72  24-3S 

These  figures  are  probably  as  trustworthy  as  any  that  have  been  made, 
as  they  were  obtained  by  recording  during  an  entire  year  the  weight  of 
milk  from  each  milking,  of  cream,  of  skim- milk,  of  butter,  and  of  butter- 
milk, and  a  determination  of  the  percentage  of  total  solids  and  fat  in  the 
milk  produced  on  five  consecutive  days  in  each  month  of  the  year.>  The 
method  of  computing  these  costs  which  are  given  here  need  not  be  con- 
sidered as  it  was  the  same  in  both  cases,  so  that  the  variations  are  due 
entirely  to  the  differences  between  the  cows.  The  figures  include  only 

*The  Maine  Experiment  Station  report  for  1889.  Part  II.,  p.  116, 


4156  BULLETIN  NO.  14.  '  [February, 

the  cost  of  the  food  the  cows  received.  A  good  reason  for  this  is  that 
feeding  stuffs  have  a  market  price  and  can  be  accurately  measured  or 
weighed,  while  the  other  expenses  of  producing  milk  can  be  best  calculated 
by  each  individual  who  owns  cows. 

Another  reference  to  the  yearly  record  before  mentioned  shows  that 
the  total  food  eaten  by  one  of  these  two  cows,  was  10,191  Ib.  and  by  the 
other  9,985  Ib.  a  difference  of  only  206  Ib.  for  the  whole  year,  and  100  Ib. 
of  this  difference  was  hay.  Or,  stating  the  case  in  another  way,  the  total 
food  eaten  by  one  cow  during  an  entire  year  exceeded  that  eaten  by  the 
other  by  106  Ib.  of  grain  and  100  Ib.  of  hay.  The  work  of  taking  care 
of  the  cows  was,  of  course,  the  same  in  both  cases.  The  production 
from  the  two  cows,  for  one  year,  was  quite  different. 

Cow  No.  I.     Cow  No.  2.     Difference. 

No.  of  days  milked 34°  322  18 

Yield  of  milk,  Ib 6,983  4,107  2,876 

"         milk  solids,  Ib  1,015.2  638.4  375.8 

"         butter  fat,  Ib  352  237.8  114.2 

"        butter,  unsalted,  Ib '  379.5  238  141.5 

Average  yield  of  milk  per  day,  Ib 202  12.7  7.5 

This  record  shows  that  cow  No.  i  gave  2,876  Ib.  more  of  milk  than 
cow  No.  2  and  that  the  excess  of  butter  produced  was  141.5  Ib.  The 
excess  of  butter,  at  25  cents  a  pound,  was  worth  $35.37;  and  the  excess 
of  milk,  at  3  cents  a  quart,  was  worth  $43.14.  Since  the  feed  and  labor 
are  practically  the  same  for  keeping  cows,  it  seems  that  it  is  quite 
worth  while  to  test  each  cow  and  see  wha*t  she  is  doing  for  her  owner. 

Tests  of  cows  nearly  as  valuable  as  the  one  just  given  can  be  made 
by  any  intelligent  person  with  the  aid  of  a  pair  of  scales;  and  probably 
many  are  doing  what  practically  amounts  to  about  the  same  thing.  The 
time  has  come,  however,  when  the  butter  value  of  a  cow  can  be  tested 
very  accurately,  and  by  the  dairyman  himself.  Until  within  about  two 
years  dairymen  were  without  any  practical  means  of  discovering  which 
one  of  three  causes,  was  responsible  for  a  small  return  of  butter  from  the 
dairy: 

1.  Whether  the  butter  fat  was  left  in  the  skim-milk. 

2.  Whether  the  cream  was  so  manipulated  that  a  considerable  amount 
of  fat  was  left  in  the  buttermilk. 

3 .  Whether  the  fault  was  in  the  cow. 

There  is  unquestionably  a  great  difference  in  the  per  cent,  of  fat  left 
in  skim-milk  even  when  the  milk  of  different  cows  is  set  under  precisely 
the  same  conditions.  A  striking  illustration  of  this  is  shown  by  the 
yearly  record  before  referred  to,  in  which  26  per  cent,  of  the  total  butter 
fat  produced  by  one  cow  was  lost  in  the  skim-milk;  while  in  the  case  of 
another  cow,  3.7  per  cent,  only  of  the  butter  fat  was  lost  in  the  skim-milk. 
.  This  difference  in  the  butter  capacity  in  cows  is  largely  overcome  by 
the  butter  extractor,  or  separator,  which  can  be  so  worked  as  to  remove 
all  but  one  to  two-tenths  of  one  per  cent,  of  fat  from  the  milk  of  any 
cow.  But  there  is  an  enormous  amount  of  butter  made  by  persons  who 


1891.]  MILK  TESTS:  METHODS  OF  TESTING  MILK.  457 

separate  the  cream  by  "setting  milk,"  and  to  them  the  thoroughness  ot 
cream  separation  is  a  matter  of  importance,  even  though  the  skim-milk  is 
fed  to  calves;  for  it  is  cheaper  to  re-inforce  skim-milk  with  grain  than  to 
feed  cream.  The  process  of  getting  the  fat  from  the  milk,  either  the 
creaming  or  the  churning,  is  at  fault,  if  the  fat  is  not  nearly  all  obtained 
by  the  butter  maker.  The  test,  if  properly  made,  or  the  analysis,  shows 
the  total  quantity  of  fat  accurately;  if  the  amount  of  butter  is  not  about 
the  same,  the  methods  of  the  butter  maker  are  somewhere  wrong.  The 
testing  of  milk  for  the  amount  of  fat  it  contains  is  no  longer  confined  to 
the  chemists  of  the  country  only.  The  process  has  been  made  so  simple 
that  it  is  hardly  an  exaggeration  to  say  that  it  is  within  the  ability  of  any 
one  who  can  turn  a  crank.  It  is  certainly  true  that  any  one  who  can 
comprehend  the  use  and  necessity  of  testing  his  cows  need  have  no  fear  of 
inability  to  manipulate  the  tester. 

The  following  record  of  work  done  in  this  direction  will  illustrate 
the  practical  use  that  a  dairyman  can  make  of  the  testers.  During 
the  past  year  I  have  tested  the  milk  of  142  cows.  This  test  was  in 
nearly  all  cases  a  determination  of  the  fat  in  the  milk  given  by  each 
cow  in  24  hours.  The  morning  milk  and  the  night  milk  were  tested 
separately  and  over  500  analyses  were  made.  Fifty  of  these  tests  are 
given  in  the  table  on  the  next  page.  In  the  table  of  extremes,  which  fol- 
lows, the  per  cents,  of  fat  in  milk,  given  in  the  columns  headed  "a.  m." 
and  "p.  m."  in  some  cases  do  not  represent  the  milk  of  the  same  cow  at 
both  milkings  at  one  farm;  but,  with  two  exceptions,  in  the  two  columns 
giving  the  milk  and  fat  produced  in  24  hours  atone  farm,  the  figures  apply 
to  the  same  cow. 

The  feed  the  cows  were  receiving  at  the  time  of  the  tests  was  as1 
follows: 

Farm  A.  The  daily  feed  to  28  head:  One  shock  of  ensilage  corn,  two 
shocks  of  sweet  corn,  and  husked  corn  from  300  hills,  equal  to  about  two 
bu.  of  ears. 

Farm  B.  Corn  ensilage,  some  shocked  corn,  and  a  little  wheat  shorts 
or  coarse  middlings. 

Farm  C.  Four  bu.  of  corn  in  the  ear  daily,  with  hay;  just  beginning 
to  feed  shorts. 

Farm  D.  One  feed  for  40  cows  is  a  mixture  of  5  bu.  corn-and-cob 
meal  ground  coarse,  2^  bu.  scalded  malt  sprouts,  and  y2  bu.  fine  linseed 
meal.  This  ration  was  fed  morning  and  evening,  also  one  feed  of  good 
tame  hay  and  one  of  corn  stover. 

The  milk  from  the  first  three  farms  is  sold  to  a  creamery;  that  pro- 
duced on  farm  D  is  mostly  used  for  making  gilt-edged  butter. 

It  may  not  be  always  fair  to  judge  of  a  cow  from  the  test  of  her 
milk  for  one  d«ay  only;  but  when  we  compare  in  this  way  cows  that  calved 
in  the  same  month,  one  important  influence  on  the  composition  of  the 
milk  is  the  same  in  both  cases.  The  thirteen  cows  tested  at  farm  A  had 
all  calved  in  June,  four  months  before  the  test  was  made.  As  they  had 


458 


BULLETIN    NO.  14. 


[February, 


RECORD  OF  TESTS  MADE  OF  MORNING  AND  NIGHT  MILK,  OR  THE  MILK  PRODUCED  IN 

24  HOURS  BY  50  COWS  ON  FOUR  FARMS. 


£ 
1 

n 

I 
2 

3 

4 

i 

7 
8 

9 

JO 

II 

12 
13 

14 

15 

1  6 

17 
18 
19 

20 
21 

22 
23 
24 
25 
26 

Breed. 

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n 

VJ 

n 

p 

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of  milk. 

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a.m. 

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Aarw  ^4,   October  28, 
Grade  Shorthorn    

r8qo. 
8 
8 

4 
5 
5 
7 
5 
7 
4 
7 
4 
5 
9 

120 
120 
1  2O 
1  2O 
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120 
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7K 
4 

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5 
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33 
3-7 
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3-3 
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3-35 
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3-75 
3  9 
3-30 

5-25 
4.78 

4 

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4.65 

3-6 
5-6 
3.85 
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3-73 
3-63 
4.86 
3.21 
4-36 
3-7i 
3-39 
4.00 
4.21 

4'!l 
4.06 

Farm  £,    October  29, 
Native  

1890. 
6[?] 
6[?] 

5 
10 
8 
7 
7 
5 
10 

5 
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5. 

28 
21 
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35 

28 
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2.8 

3 
3-3 
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3-i8 
3-4i 
3-43 
3-32 
3-27 
3.26 

3-96 
3-68 
4.11 
3-64 
4-52 
3-94 

Grade  Holstein   

Grade  Shorthorn  .  .    .    . 

Grade  Holstein  

Native  

Jersey  and  Holstein  

z 

29 

30 
31 

32 

33 

34 
35 

36 

ii 

39 
40 

4i 
42 
4j 
44 
45 
46 

s 

4< 

;o 

Farm  C,   October  jo, 
High  grade  Shorthorn  

1890. 
8 

3 
6 

2 

6 

2 

3 

2 

210 
42 
90 
120 

'So 

'5° 
1  20 

£ 

60 

?* 

13 

7 

6 
9 

7# 

5 
7 
»3 

6 
6 
6 

6 

7 

3-2 

3-9 
3-3 
4.6 
4.6 
4.6 

4-6 
3-4 

2 

3-9 
3-3 
38 

4-4 
4-7 
4-7 
4 
3 

14 

14^ 
26 

14 
13 

14 
12 

14  14 

.388 

-565 
.858 
.588 
.586 
•65 
•58 
•65 
•456 

2-77 
3-89 
3.30 
4.20 

4-5° 
4.64 
4-83 
4-33 
3.20 

Native   ...       

High  grade  Shorthorn  

Half  Hereford  

Native  

Half  Hereford  

Native  

Native   

Farm  D,  January  j, 
Grade  Shorthorn  

1891. 

4 

10 

5 
7 

12 

7 
3 
8 

4 
3 
5 
7 
o 

120 
270 
ISO 
1  2O 
240 

ISO 
240 
27O 
'SO 
90 
120 
1  2O 
00 
00 
60 

12 

K 

8M 
13 

5X 
8^ 

7X 
534 
7K 
H# 
ilk 

8M 
io# 

13 

12  U 

103^ 

7^ 

7^ 

[2 

ix 
JK 

8 

13 

io}i 

9K 
9^ 

12^ 
12  1A 

3-48 
4-13 

3-7 

3-8 

3-4 
Lost 

4 

!:i 

3-3 
3-5 
3-4 
3-3 
i 

3-7 
49 
3-5 
3-2 
4-3 
4  2 
3-2 
3-8 
3-4 

2.6 

3-3 
3-4 
3-4 
3 

2.7 

22^ 

16 
i6>i 
25 
9K 
16^ 

;^ 

tS3^ 

24  % 

2l3/8 
W/2 
20^ 

25^ 

?.*v< 

.82 
.72 
•  59 

is 

•63 

3-6o 
4-5° 
3-57 
3  12 
4.00 
3.81 

Grade  Jersey  

Native   

Native   

"Grade  Jersey  

Grade  Shorthorn  

Native       ...        ... 

Native  

.46 

•S2 
.76 

.70 

•65 
.69 

•79 

.70 

3-9» 
3-42 
3.10 

3-27 
3-5i 
3-40 

3-" 

2.88 

Grade  Shorthorn.      ...        

« 

Cl 

«< 

M 

Grade  Jersey  

Native  .  . 

MILK  TESTS:  METHODS  OF  TESTING  MILK. 


459 


TABLE  SHOWING  A  SUMMARY  OF  EXTREMES  AND  AVERAGES  OF  THE  TESTS  OF  THE  50 

COWS  AT  THE  FOUR  FARMS. 


Highest. 

Lowest. 

Average. 

Per  cent, 
of  fat. 

Produced 
in  24  hours, 
Ib. 

Per  cent, 
of  fat. 

Produced 
in  24  h'rs, 
Ib. 

Per  cent, 
of  fat. 

Produced 
in  24  hours. 
Ib. 

a.m. 

p.  m. 

Milk. 

Fat. 

a.m. 

p.  m. 

Milk. 

Fat. 

a.m. 

p.  m. 

Milk. 

Fat. 

Farm  A  

5 
5-4 
5 
4-1 

5-6 

4-7 
47 
4.9 

*5X 

38 
26 

25K 

.62 
1.24 
.86 
.82 

3 
32 
3-2 
3 

3-6 

2.6 
2 
2.6 

8^ 

17* 

12 

9'/2 

•3 

•  7 
•39 
•38 

3-6 
4 
4-i 
3-5 

4-4 
3-4 
3-75 
3-5 

ii-5 

25 
15 
19 

.46 
•9 

I9 
•65 

Farm  B  

FaAi  C   

Farm  D  

Average  

49 

S.4 

4.98 
1.68 

26% 
rf 

.885 
1.24 

31 
T 

2.7 

2 

II  9 

8'/ 

•52 

.T 

3-8 

3-76 

18.5 

•65 

Extreme.  . 

all  Tiad  the  same  treatment,  were  of  the  same  grade,  and  were  all  mature 
animals,  the  task  of  selecting  the  most  profitable  butter  cows,  or  of 
weeding  out  the  poor  ones  is  not  very  complicated.  The  average  quan- 
tity of  milk  given  per  cow  in  24  hours  was  n^  Ib.,  the  most  milk 
given  by  any  one  cow  was  15^  Ib.,  the  least  8^  Ib.  The  cow  giving  the 
most  milk  produced  the  largest  quantity  of  butter  fat — .62  Ib.  The  cow 
giving  the  least  milk  produced  the  least  fat — .3  Ib.  The  average  weight 
of  butter  fat  produced  per  cow  was  .46  Ib.,  or  a  little  less  than  half  a 
pound.  On  the  basis  of  the  weight  of  butter  fat  produced,  the  best  cow  in 
this  lot  gave  100  per  cent,  more  butter  fat  than  the  poorest,  and  there  were 
five  other  cows  that  were  producing  less  than  63  per  cent,  of  the  best  cow's 
product,  while  four  of  the  cows  came  within  8  per  cent,  of  being  as  good 
as  the  best  one.  Further  inspection  of  the  table  shows  that  there  were 
six  other  cows  from  the  different  farms,  Nos.  30,  33,  36,  39,  46,  and  47, 
that  had  been  milked  about  the  same  length  of  time  since  calving.  Four 
of  these  produced  over  100  per  cent,  more  butter  fat  than  cow  No.  4, 
the  poorest  one  in  the  comparison  just  made.  Comparing  No.  36  and 
No.  39  shows  that  the  most  butter  fat  is  not  always  produced  by  the  cow 
giving  the  most  milk. 

At  farm  B  thirteen  cows  were  selected  that  were  all  fresh  in  milk, 
having  calved  within  a  month.  The  average  quantity  of  milk  given  per 
cow  in  24  hours  was  25  Ib.;  the  most,  38  Ib.;  and  the  least  17^  Ib.  In 
this  case,  the  most  butter  fat  was  produced  by  the  cow  giving  the  most 
milk,  the  38  Ib.  of  milk  containing  i^  Ib.  butter  fat;  and  the  least  butter 
fat  was  found  in  the  milk  of  the  cow  giving  the  least  quantity,  17^  Ib., 
and  amounted  to  .7  Ib.  The  average  weight  of  butter  fat  given  per  cow, 
per  day,  was  .9  Ib.  Measured  by  the  weight  of  butter  fat  produced  in  24 
hours,  this  lot  of  cows  was  much  more  uniform  than  the  one  previously 
mentioned.  The  best  cow  of  this  lot  was  only  77  per  cent,  better  than  the 
one  giving  the  least  butter  fat  on  this  day;  while  in  the  previous  compari- 
sons the  best  was  over  100  per  cent,  better  than  the  poorest. 


460 


BULLETIN    NO.   14. 


[February, 


Granting  that  there  is  a  vast  difference  in  cows  because  of  their  varied 
capacity,  it  at  once  becomes  evident  how  unfair  it  is  to  the  patrons  of 
a  creamery  to  pay  each  and  all  of  them  the  same  price  per  pound  for  the 
milk  they  bring,  no  matter  whether  it  contains  3  or  6  per  cent,  of  butter 
fat. 

Tests  made  at  Creameries.  The  following  table  shows  a  record  of 
tests  made  of  milk  brought  by  78  patrons  to  two  creameries  in  one  day: 

RECORD  OF  TESTS  MADE  OF  MILK  BROUGHT  BY  78  PATRONS  TO  TWO  CREAMERIES  IN 

ONE  DAY. 


Per  cent, 
fat  in 
milk. 

Creamery  A—  October  31,  1890. 

Creamery  B  —  October  30,  1890. 

Pounds 
milk. 

Pounds, 
fat. 

Pounds 
of  milk 
per  Ib. 
of  fat. 

No.  of 
patrons 
contibut- 
ing. 

Pounds 
milk. 

Pounds 
fat. 

Pounds 
of  milk 
per  Ib. 
of  fat. 

No.  of 
patrons 
contrib- 
uting. 

3-3 
3-4 
3-5 
3-7 
3-8 
3-9 
4 
4-i 

4-2 

4-3 
4-4 
4-5 
4.6 

4-7 
4.8 

4-9 
5 
5-i 

5i 
5-6 
6.4 

164 

243 
256 

5-412 
8.262 
8.960 

30.3 

27 
26.3 
25.6 
25 
24-3 
23  8 
23.2 
22.7 

22.2 
21.7 
21.3 
20.8 
2O.4 
20 

I 
I 

I 

236 
820 

8.712 
31.160 

27 
26,3 

i 

4 

493 
138 
I.I34 
1,412 
1,268 
772 
290 

3" 

299 

24 
229 

95 

242 

18.734 
5-382 
45-36o 
58.092 
53-256 
33-I96 
12.760 

13-995 
13-754 
1.128 
10.992 
4.655 

12.100 

3 

i 

7 

6 

5 

2 

3 

5 

i 

2 
2 
2 

655 
147 
725 
600 
407 

26.200 
6.027 

3°-45° 
25.800 
17.910 

25 
24-3 
23-8 
23.2 
22.7 

3 

i 

4 
3 

5 

666 

30.643 

21.7 

4 

65 

3-185 

20.4 

i 

72 

3.672 

19.6 

2 

88 

4-576 

19.2 

I 

81 

12 

4-536 
.768 

17.8 
15.6 

I 
I 

Total.  .  . 

7,458 

310.624    1      24 

48 

4,496 

190.060 

22.4 

30 

At  creamery  A  the  average  per  cent,  of  fat  in  the  milk  brought  by  the 
48  patrons  was  4.25;  the  highest,  5.2;  the  lowest,  3.3,  or  to  make  one 
pound  of  butter  fat  would  require  19.2  Ib.  of  milk  in  one  case  against 
30.3  Ib.  of  the  poorest  milk  brought. 

At  creamery  B,  supplied  by  30  patrons,  the  best  milk  brought  was  57 
per  cent,  richer  in  butter  fat  than  the  poorest  milk. 

The  difference  between  the  yield  of  butter  by  the  churn  and  of  butter 
fat  by  the  tests,  is  the  water,  salt,  and  curd  of  the  butter. 

In  the  record  of  creamery  A,  as  given  above,  the  butter  fat  as  found 
by  test  was  310.62  Ib.;  the  yield  of  the  churn  that  day  was  333.5 — an  in- 
crease of  the  churn  over  the  test  of  22.88  Ib.,  or  7.36  per  cent. 

The  following  table  illustrates  the  method  used  by  Gurler  Bros.,  De- 
Kalb,  111.,  at  the  creameries  where  the  patrons  are  paid  on  the  test  plan. 
The  milk  brought  by  each  patron  is  tested  once  each  week;  an  average  of 
these  tests  is  made  every  month;  the  total  pounds  of  milk  brought  by 


1891.] 


MILK    TESTS:    METHODS    OF   TESTING   MILK. 


461 


each  patron  during  the  month  is  multiplied  by  his  average  per  cent,  for  the 
month,  the  total  amount  being  the  total  pounds  of  butter  fat  by  test. 
Dividing  the  total  number  of  pounds  of  butter  fat,  as  shown  by  the 
test,  delivered  by  all  the  patrons  by  the  difference  between  this  number 
and  the  actual  yield  of  butter  by  the  churn  gives  the  per  cent,  of  increase 
of  the  churn  over  test.  (Taking  the  illustration  below:  698.92—602.56— 
96.36;  96.36-5-602.56=1.16.  Increase  of  churn  over  test=:i6  per  cent.) 
Adding  then  to  the  number  of  pounds  of  butter  fat  delivered  by  each 
patron  16  per  cent,  of  that  number  gives  the  number  of  pounds  of  butter 
with  which  he  is  credited  and  for  which  he  is  paid. 

TABLE  SHOWING  METHOD  OF  PAYING  CREAMERY  PATRONS  ON  THE  BASIS  OF  THE 
AMOUNT  OF  BUTTER  FAT  IN  MILK  DELIVERED. 


3 

Per  cent,  fat  in  milk  as  shown 
by  tests. 

cu?r 

i—  i 

3 
0 

f? 

X 

a 
n 

T3  r1 

Ss-F 

» 
n 
o 

n> 

0    ^ 

cr  2. 

3 

2 

| 

* 

5! 

<S 

3  cr 

nT  £• 
oo  £> 

O 

3§ 
o-o- 

< 
ft 

&. 

8& 

5=? 

-  n> 

§.  o- 

< 

J 

* 
* 

P 

II 

£ 

0 

3- 

f, 

f*  g. 
n 

o" 

•-( 

B  3 
S.  P 

Sro1 

•       "-I 

' 

*" 

vp 

P1 

?% 

o- 

*-t 

3 

tr 
c 

ff"  n 

8 

0 

ft 

i 

3-7 

3-6 

3.7 

4-2 

3-8 

1,556 

59  -!3 

ft 

1 

68.59 

M 

4.40 

$1.05 

2 

4 

* 

* 

3-7 

3-85 

474 

18.25 

ft 

21.17 

4.46 

.06 

3 

3-8 

4 

3-7 

3-9 

CrvX 

170  06 

^ 

I97-30 

0 

fn 

4-52 

5 

4 

3-9 

4i 

4-03 

59s 

4,621 

186.23 

o-. 

3O-31 
216 

3 

5T 

.07 
4.67 

.12 

6 

4-3 

4-3 

4-8 

4-4 

4-45 

2,967 

132.03 

a 

153  13 

T3 

5-16 

•23 

7 

4-4 

4-7 

3-5 

42 

4.20 

255 

10.71 

0 

m 

12.42 

"1 

4-87 

.16 

Total  . 

602.  >;6 

3 

608.  02 

*No  milk  delivered. 

A  report  of  one  of  their  creameries,  made  by  Gurler  Bros,  for  Octo- 
ber, shows  that  the  patrons,  who  were  there  paid  on  the  test  plan,  received 
from  93  cts.  to  $1.32  per  100  Ib.  of  milk. 

The  time  and  labor  of  the  patrons  was  probably  the  same  for  pro- 
ducing the  100  Ib.  of  milk  that  brought  93  cts.,  as  for  that  which  brought 
$1.32,  and  it  has  been  demonstrated  that  the  test  is  trustworthy;  so  there 
seems  to  be  but  one  conclusion  to  draw — the  cows  need  testing. 

METHODS  OF  TAKING  SAMPLES  OF  MILK  TO  BE  TESTED. 

When  any  milk  is  to  be  tested  a  great  deal  of  care  is  necessary  to  get 
a  fair  sample  of  it.  Even  new  milk  should  be  poured  from  one  vessel  to 
another.  When  the  cream  has  risen  on  milk  it  can  be  mixed  again  by 
warming  the  milk  to  about  the  temperature  of  the  body,  100°  F.,  and 
carefully  pouring  it  back  and  forth  from  one  vessel  to  another  until  no 
small  lumps  of  cream  can  be  seen  or  known  to  be  present.  Shaking  or 
stirring  the  milk  in  one  vessel  may  separate  the  butter  fat  by  churning  it, 
and  cannot  safely  be  substituted  for  pouring. 


462 


BULLETIN    NO.   14. 


[February, 


S 


.,-.  3 


Fig.  3  shows  an  arrangement  used  by  Gurler  Bros.,  DeKalb,  111.,  in 
taking  samples  for  testing  the  milk  brought  to  a  creamery  by  its  patrons. 

The  milk  runs  from  the  weighing  can  A  through  the  conductor  D  to 
the  tank  C.  The  brass  tube  E  is  about  2}^  to  3  ft.  long,  with  an  inside 
diameter  of  3-16  to  4-16  in.  (The  end  over  the  small  pail  should 
be  turned  down.)  This  brass  tube  lies  in  the  conductor  spout,  extending 
out  about  one  foot,  and  a  small  pail  F  is  hung  under  the  end  to  catch  the 
milk  that  runs  through  the  brass  tube  while  the  milk  in  the  weighing  can 
A  is  running  through  D  into  C.  The  weight  of  the  brass  tube  holds  it 
in  place.  The  milk  collected  in  this  way  in  the  pail  F,  when  mixed,  is 
ready  for  making  the  test. 

COMPARISON  OF   DIFFERENT  ""MILK   TESTS"   WITH  EACH  OTHER  AND  WITH  GRAVI- 
METRIC LABORATORY  ANALYSIS  ON  THE  SAME  SAMPLE  OF  MILK. 

In  bulletin  No.  10  of  this  Station  a  report  was  published  of  observa- 
tions made  with  several  milk  tests.  These  included  "  Short's  test,"  The 
Iowa  Station  "  Milk  Test,"  described  by  Patrick,  and  the  Cochran 
"  Milk  Test." 

Since  that  time  Professor  Patrick  has  suggested  the  use  of  a  brine 
bath  in  connection  with  his  test,  and  two  other  tests  have  been  made 
public:  the  Beimling  "  Milk  test,"  described  in  bulletin  No.  21,  Vt.  Exper- 
iment Station,  and  Dr.  Babcock's  "  Milk  Test,"  bulletin  No.  24,  Wis.  Ex- 
periment Station. 

By  the  use  of  the  brine  bath  with  the  Patrick  test,  a  number  of  tests 
can  be  carried  on  at  the  same  time  and  kept  at  a  uniform  stage  in  the 
process.*  The  details  of  this  test  have  been  very  thoroughly  worked  out 
by  its  author  and  satisfactory  results  have  so  far  been  obtained,  except 


^Bulletin  n,  la.  Experiment  Station,  page  484. 


1891.]  MILK  TESTS:  METHODS  OF  TESTING  MILK.  463 

Notes  on  the  Babcock  Test.  When  a  large  number  of  tests — 30  to  60 — 
•are  to  be  made  by  this  method,  each  test  bottle  can  be  set  in  boiling  hot 
water,  as  soon  as  the  acid  and  milk  have  been  thoroughly  mixed.  This 
keeps  them  hot  till  all  are  ready  to  be  put  in  the  centrifuge,  and  helps  to 
get  a  clear  and  complete  separation  of  fat. 

The  appearance  of  a  white  residue  that  is  not  fat,  mixed  with  the  fat, 
or  forming  a  layer  between  it  and  the  other  liquid  in  the  test  bottle,  is 
prevented  by  use  of  acid  of  the  right  strength. 

The  specific  gravity  of  the  acid  recommended  by  Dr.  Babcock  is 
1.82.  The  bottle  of  sulphuric  acid  must  be  tightly  corked  when  not  in 
use,  because  of  the  property  this  acid  has  of  taking  up  from  the  air 
moisture,  which  dilutes  the  acid  and  weakens  its  action  on  the  milk. 

The  greatest  accuracy  is  obtained  by  testing  milk  when  it  is  about  the 
temperature  of  the  body,  and  by  measuring  the  column  of  separated  fat 
at  a  temperature  of  140°  F. 

Notes  on  the  Beimling  Test.  The  graduations  for  measuring  the  fat  in 
the  test  bottles  are  very  fine,  so  that  strong  eyes  and  light  are  necessary 
for  reading  the  results. 

The  graduations  do  not  represent  percentages  of  fat,  but  a  "ready 
reckoner"  card  is  required  which  contains  the  per  cents  of  fat  correspond- 
ing to  the  graduations. 

Two  "compounds"  must  be  added  to  each  test,  and  the  amount  used 
of  compound  No.  2  is  a  variable  quantity,  because  the  test  bottles  are 
not  of  a  uniform  size,  and  the  compound  must  be  added  till  the  neck  of 
the  bottle  is  filled.  This  may  be  the  reason  why  more  heat  is  developed 
in  one  test  than  in  another. 

A  proper  mixture  of  the  milk  with  the  chemicals  in  the  test  bottles 
often  caused  such  a  foaming  that  the  liquid  spurted  out  and  the  test  was 
lost. 

The  safest  method  of  manipulation  I  found  to  be  first  thoroughly  to 
mix  compound  No.  i  with  the  milk  in  the  test  bottle,  then  to  add  com- 
pound No.  2  in  successive  portions,  mixing  after  each  addition.  In  nearly 
every  test  that  I  have  made  by  this  process  it  has  been  necessary  to  add 
hot  water  after  running  in  the  centrifuge  in  order  to  bring  the  fat  up  into 
the  neck  of  the  test  bottle  where  it  is  measured. 

The  tests  must  be  made  in  a  warm  room,  otherwise  when  making  6 
•or  more  tests,  the  first  one  cools  before  the  last  one  is  ready  to  be  put 
into  the  centrifuge. 

With  some  skim-milks  this  test  gives  too  high  results — probably 
caused  by  the  fusel  oil  in  compound  No.  i  which,  if  not  expelled  by  the 
heat  developed  or  the  certrifugal  motion,  may  accumulate  in  the  neck  of 
the  test  bottle  and  be  measured  as  butter  fat. 

Professor  W.  W.  Cooke  says  in  bulletin  Ao.  2f,  Vt.  Experiment  Station, 
•"A  rough  idea  of  the  fat  percentage  in  skim-milk  and  buttermilk  may  be 
obtained  by  this  [Beimling]  method,  but  they  cannot  be  accurately 
analyzed  unless  there  be  at  least  a  [one]  per  cent,  of  fat  present." 


464 


BULLETIN    XO.   14. 


[February, 


The  results  given  on  page  465  with  skim-milk  by  this  method  were 
obtained  by  running  the  centrifuge  two  minutes  and  then  stopping,  except 
No.  533.  In  this  case  the  skim-milk  was  from  a  separator.  The  trials 
were  all  made  upon  portions  of  milk  taken  from  the  same  sample.  In 
each  of  the  five  trials  made  by  the  Beimling  method  the  centrifuge  was 
run  two  minutes,  stopped,  and  the  reading  of  the  fat  taken.  It  was  then 
run  two  minutes  more  and  a  second  reading  taken;  and  the  same  was 
done  for  third  and  fourth  periods  of  two  minutes  each.  A  repetition  of 
this  trial  by  the  Beimling  method  gave  as  an  ultimate  result  with  each  of 
six  portions  .69  per  cent,  of  fat.  The  table  shows  the  details. 

PERCENTAGE  OF  FAT  FOUND  BY  REPEATED  TRIALS  BY  DIFFERENT  METHODS  ox  ONE 
LOT  OF  SEPARATOR  SKIM-MILK. 


Beimling. 

[Centrifuge  run  for  2  minutes  before 

Gravimetric. 

Patrick. 

Babcock. 

each  reading.] 

Cochran. 

First  2 

Second 

Third  2 

Fourth  2 

min. 

2  min. 

mm. 

mm. 

0.25 

0.25 

0.25 

0.26 

0.52 

0.69 

0.78 

0-35 

o  25 

0.30 

0.25 

035 

0.69 

o  69 

0.78 

0.47 

o  20 

o.^o 

o.-iz 

0.61 

0.60 

0.78 

O    14. 

o  ^o 

O  4"* 

0.61 

o  61 

0.78 

0.52 

0.52 

o  61 

o  78 

TABLE  SHOWING  MILK,  TIME,  CHEMICALS,  AND  COST  OF  CHEMICALS  REQUIRED  FOR 
EACH  ANALYSIS  BY  THE  THREE  METHODS  NAMED. 


Method  of 

Milk   per 
analysi 
c.  c. 

Reagents  or  chemicals 
used. 

Time  for  single  analy- 
sis,   approximate. 

Estimated     cost      for 
chemicals,per  analy- 
sis. 

Patrick. 

10.4 
I 

*"Acid     mixture," 
about  10  c.  c. 

About  20  minutes. 
"Six  analysis  in  one- 
half  hour." 

"Acid  mixture"  2octs. 
per  Ib.  "One  Ib. 
makes  25  tests." 

Babcock. 

17-6 

"Com.  sulphuric  acid, 
about    90     per    cent, 
pure.     Sp.  gr.   1.82." 

"Sixty  tests  may  be 
made  in  less  than  two 
hours." 

One-half  to  one-fifth 
of  a  cent. 

Beimling. 

IS- 

3  c.   c.  of  fcompound 
No.  I.     "Fill  the  bot- 
tle compound  No.  2** 
to  the  o  mark." 

"Five  minutes,"  or 
25  tests  an  hour. 

"Less  than  one-fifth 
of  a  cent  per  test." 

*  "Acetic  acid  [90  per  cent.]  9  volumes;  commercial  oil  of  vitrol,  sp.  gr.  1.83,  5  to 
6  volumes.  Mix,  allow  to  cool,  and  add  to  the  mixture  about  2  per  cent,  by  volume  of 
rectified  methylic  alcohol." 

f  "Mixture  of  equal  bulks  of  rectified  amyl  alcohol  and  com.  cone,  hydrochloric 
acid,  sp.  gr.  1.16  or  above." 

**  Commercial  concentrated  oil  of  vitriol,  sp.  gr.  1.83. 

The  gravimetric  methods*  used  for  analysis  of  the  milk  were  the 
Adams  paper  method,  the  sand  method,  by  which  the  milk  is  first 
dried  at  iooc  C.  on  about  20  grams  cleansed  sand,  the  dried  residue  and 

*5  c.  c.  Milk:  weighed  from  weighing  bottle  each  time. 


MILK  TESTS:  METHODS  OF  TESTING  MILK. 


465 


TABLE  SHOWING  PERCENTAGES  OF  BUTTER  FAT  FOUND  IN  SAMPLES  OF  WHOLE  MILK, 

SKIM-MILK,  AND  BUTTERMILK  BY  GRAVIMETRIC  METHODS,  AND  BY  THE 

BABCOCK,  THE  PATRICK,  AND  THE  BEIMLING  "MILK  TESTS." 


\ 

r 
S- 

2 

p 

Gravimetric  methods. 

Babcock. 

Patrick. 

Beimling. 

Adams'. 

Sand. 

Asbes- 
tos. 

Milk  of  one  cow  

495 

\  2.OI 
1  2.10 

2.00 

2.07 

2.00 
1.97 

2.OO 

1.90 

2.OO 

2.30 

2.00 

2.30 

<i            11 

496 

I  2.70 
1  2-77 

2.61 

2.82 

2.65 

2-5' 

2-55 
2.50 

2.60 
2.70 

2.61 
2.70 

11           n 

497 

If'*9 

]6.23 

S15 

6.14 

6  14 

6.10 
6.  20 

6.10 

6.20 

6.18 
6.18 

<!                      <1 

498 

j  5-43 
1  5-43 

5-44 
5-41 

5-35 
5.09 

540 
5-30 

5-40 
5-30 

5.40 
5.50 

4( 

499 

4.26 

4-34 

4.10 

4-35 
4.40 

4.20 
4  20 

4-35 
4.44 

«                      l< 

500 

j  '-95 

|  2.  II 

I  87 

i.  80 

1  95 
1.88 

1.80 
'.85 

i.  80 
1.  80 

'.83 
1.91 

<1                       « 

502 

(6.43 
]6.49 

6.38 
6.33 

6.32 
6.32 

635 

0.2O 

6.40 
6.40 

6.38 
6.44 

(1                       11 

501 

5-44 

5-45 

5-30 

J5-35 
15-30 

5-35 
5-40 

5-50 
5-58 

(1                      « 

520 

5-29 

5  '3 

5.00 

U.oo 
IS-™ 

500 
5.10 

5-'3 
5.22 

11                      « 

522 

6.29 

6.23 

6.01 

I  6.00 
16.00 

6.00 
6.  20 

6.18 
6.  10 

«                      « 

527 

4  05 

3-93 

3-8' 

(4-00 
l4-oo 

4.10 
4.00 

4.17 

4.00 

<1                       (1 

526 

6.06 

6.08 

58' 

j  6.00 
15-90 

5-90 
5-90 

5-83 
5-9' 

Skim-milk    

5^9 

o-54 

0.42 

0-43 

(050 
lo.40 

0.40 
o-35 

0-43 
0.52 

ii         ii 

525 

j  1-44 
1  1-44 

i-35 
1.32 

1.27 
1.24 

1.40 

1.40 

'•35 
1.40 

1.48 

«         ti 

53' 

jo.  23 
1  o.io 

0.18 
0.17 

0.15 

0.12 

0.2O 
0.30 

o.o 

0.26 
0-35 

11         11 

532 

(0.48 
lo.49 

0.41 
0.24 

O.2O 
0.24 

0.40 
0.40 

0.30 

0.20 

0-43 
0.26 

Separator  skim-milk.  . 

533 

jo.  25 
(0.25 

O.2O 
O.I4 

0.25 
0.30 

O.25 
0.30 

0.69 
0.78 

Buttermilk    

524 

jo.  37 
1  0.32 

0.41 

0.50 

0.45 

0.0 

0.44 
0-39 

it         « 

523 

*o.56 
{0.55 

o-59 

0-5' 
0.50 

0.50 
0-45 

o.o 

0.43 
0-43 

"         »    

53° 

*o-47 
(0.38 

0-33 
0.44 

0.80 
0.80 

0.0 

0.70 
0.70 

466 


BULLETIN    NO.   14. 


\_February, 


sand  transferred  to  a  fat  extractor;  and  an  asbestos  method  operated  as- 
follows:  A  tube  3  in.  long  and  7/i  in.  in  diameter  was  made  of  thin  sheet- 
brass  punched  with  holes  1-25  in.  in  diameter.  One  end  of  the  tube  was 
closed  with  this  sheet-brass.  The  tube  is  filled  with  clean,  fibrous  asbes- 
tos and  weighed;  the  weighed  quantity  of  milk  is  run  upon  this  asbestos, 
and  the  whole  dried  at  100°  C.  When  dry,  this  tube  is  transferred  to  the 
fat  extractor. 


A  DEVICE  FOR  MEASURING  THE  ACID  INTO  THE  TEST   BOTTLES 

BABCOCK'S  METHOD. 

Fig.  i  shows  the  glass  bottle,  or  carboy, 
A  which  holds  the  acid.  The  neck  is  closed 
by  a  tight-fitting  rubber  stopper.  There  are 
two  holes  in  the  stopper.  One  is  for  letting 
air  into  the  bottle  as  the  acid  is  drawn  out; 
at  other  times  it  is  tightly  closed  by  the  cork 
B.  The  glass  tube  D  passes  through  the  other 
hole  in  the  stopper  nearly  to  the  bottom  of 
the  vessel  A,  and,  as  shown  in  the  cut,  con- 
nects with  a  glass  burette  E  by  means  of  a 
three-way  glass  stop-cock. 

When  the  cork  B  is  taken  out,  the  siphon 
tube  D  being  full  of  acid  and  the  glass  cock 
in  the  position  shown  in  the  cut,  the  acid  will 
run  in  and  fill  the  burette  E,  provided,  of 
course,  there  is  sufficient  acid  in  the  vessel  A. 
When  the  burette  E  is  as  full  as  desired,  that 
is,  when  the  surface  of  the  liquid  cuts  the 
line  a,  b,  c,  or  g,  the  flow  of  acid  from  A 
through  the  tube  D  can  be  stopped  by  turn- 
ing the  glass  cock  F  H  until  F  H  is  horizon- 
tal instead  of  vertical.  Then  by  turning  the 
cock  still  more  so  that  F  and  H  change  places, 
the  acid  is  shut  off  from  D  and  direct  con- 
nection is  made  between  the  burette  and  the 
tube  K,  allowing  the  acid  to  flow  into  the  test 
bottle  M.  When  the  required  volume  of  acid 
has  run  into  M,  as  indicted  by  the  lines  on  the 
burette,  the  stop  -cock  is  turned  so  as  to  shut 
off  the  flow  of  acid,  and  another  test  bottle 
takes  the  place  of  the  first  one  and  receives 
its  charge  of  acid. 

A  suitable  support  for  the  burette  E  is  a 
simple  matter  and  can  be  adjusted  by  any 
one.  Either  attach  the  burette  to  a  board  by 
a  wire  or  clamp  it  to  a  wooden  or  iron  rod. 
The  length  of  the  burette  will  depend  on 
how  many  measures  of  acid  it  is  to  hold. 


USED   WITH  DR. 


\ 


MILK  TESTS:  METHODS  OF  TESTING  MILK. 


467 


11.5 
C.C 


There  are  advantages  in  using  an  automatic  pip- 
ette, Fig  2,  in  the  place  of  the  burette  E.  With  this 
pipette  there  can  be  no  mistake  made  in  the  quantity 
of  acid  measured  out,  if  the  pipette  is  filled  each  time. 

The  diameter  of  the  tubes,  and  passages  of  the 
cocks  through  which  the  acid  runs,  should  be  at  least 
3-16  in.  so  that  the  thick  acid  will  run  freely  and  not 
too  slowly. 

When  not  in  use  the  glass  cock  should  be  left  in 
such  a  position  that  the  acid  will  drain  out  of  it.  By 
this  arrangement  the  acid  is  kept  tightly  corked;  it  is, 
ready  for  use  at  any  time,  and  there  is  less  chance  of 
waste  or  pouring  over  the  hands  and  clothing. 

The  apparatus  illustrated  in  Fig.  i  has  been 
made  by  a  dealer  in  chemical  apparatus  for  $2.50; 
that  in  Fig.  2,  which  must  have  with  it  the  bottle  A 
and  tube  D,  for  $2.25. 

CHEMICAL  ANALYSES  OF  "GERM  MEAL"  AND  OF  "OAT  DUST 
FEED." 

The  price  of  corn  and  oats  during  the  present 
season  causes  certain  bye  products  of  manufacturing  processes  to  come 
into  more  prominent  notice  as  feeding  stuffs.  Two  such  have  been 
analyzed  from  samples  taken  in  November,  1890. 

The  germ  meal  was  out  of  a  car  load  from  which  farmers  were  buying 
at  DeKalb,  111. 

The  oat  dust  feed  was  obtained  from  the  Rockford  Oat  Mills,  Rock- 
ford,  111. 

The  following  table  gives  the  analyses,  together  with  an  average  of  a 
great  many  analyses  of  some  other  common  feeding  stuffs: 

TABLE  SHOWING  COMPOSITION  OF  "  GERM  MEAL"  AND  "  OAT  DUST  "  FEED  IN  COM- 
PARISON WITH  OTHER  WELL  KNOWN   DEEDING  STUFFS. 


Composition  of  dry  feed  contain- 
ing no  water. 

'Composition  (as  fed)  when 
analyzed. 

H 
S'S 

n 

•< 

n 
o 

JJ 

3 

n 

EL 

B  O 
n  <!> 

^3 

O 

s"~ 

£L  CL 
I 

*3 
P| 

0 
£• 

r 

H 

6*1 

x  2, 

•  tf 
*< 

n 

o 

1-1 

3 
n 

JL 

3  0 

re  n 
^ 

0 

JT£ 
n 

o.  a. 

•      C 

0-3 

n 

o 

p 

y 

Water  

10.24 
4.11 
6.06 

2.12 

47.10 
30.37 

15-93 
1.46 
9.16 
3-81 
67.84 
i.  80 

9 
i.  02 
11.56 
6.40 
62.72 
9-3o 

7.91 
7-63 
12-37 
4.25 

47-47 
20.37 

12.48 
5-70 
15-07 
3.78 
54.26 
8.7i 

10.94 

3.97 
11.38 
4.81 
60.05 

9-85 

Ash  

466 
5.74 
2.36 
52.49 
33-85 

1-73 
10.89 

4-53 
80.70 

2-15 

1.  12 

12.70 

7-t-3 
68.94 

IO.2I 

8.28 

13-43 
4.6l 

51-54 
22.12 

6-53 
17.21 

«4'31 
62 

9-95 

3-31 
12-70 

5-41 
67.44 
II.  06 

Protein    

Fat  

N.-free  ex't  

Fiber  

No.  of  analyses   ... 

53 

56 

I 

I 

63 

25 

468  BULLETIN  NO.  14.  {February,  1891. 

In  using  this  or  any  other  table  of  feeding-stuff  analyses,  it  should  be 
remembered  that  chemical  analyses  of  feeding  stuffs  serve  as  a  guide 
only  for  judging  one  by  another,  and  that  the  palatability  and  digestibility 
help  to  measure  their  value  as  food  as  well  as  the  quantity  of  protein,  and 
other  constituents. 

In  this  analysis  the  germ  meal  somewhat  resembles  oats.  If  one  can 
be  taken  as  the  equivalent  of  the  other  in  feeding  value,  what  can  be 
made  by  selling  a  crop  of  oats  and  buying  germ  meal  ? 

A  ton  of  oats,  63  bu.  to  the  ton,  at  45  cts.  per  bu.  is  worth $28.35 

Germ  meal,  in  car  load  lots,  per  ton 16.00 

When  such  a  calculation  as  this  is  made  it  should  not  be  forgotten 
that  these  are  prices  for  the  products  at  market,  and  that  the  apparent 
profit  of  the  transaction  should  be  diminished  both  by  the  cost  of  market- 
ing the  oats  and  the  cost  of  bringing  the  germ  meal  to  the  farm.  Also  it 
should  not  be  forgotten  that  the  manufactured  feed  can  often  be  easily 
adulterated  with  less  valuable  food  so  that  it  might  be  essential  for  the 
buyer  to  protect  himself  by  a  guaranty  of  purity,  and  by  an  analysis  of 
a  sample  from  the  stock  offered  him. 

The  oat  dust  feed  contains  a  high  per  cent,  of  fiber,  not  so  much  as 
timothy  hay  but  a  great  deal  more  than  oats.  The  nitrogen-free  extract 
is  also  about  like  that  of  timothy  hay  and  much  less  than  in  oats.  The 
protein  is  equal  in  quantity  to  that  of  oats,  while  the  ash  is  considerably 
higher.  An  examination  of  the  ash  showed  that  it  contained  about  fifty 
per  cent,  of  insoluble  matter  (sand,  etc.). 

E.  H.  FARRINOTON,  M.  S.,  Assistant  Chemist. 


All  communications  intended  for  the  Station  should  be  addressed, 
not  to  any  person,  but  to  the 

AGRICULTURAL  EXPERIMENT  STATION,  CHAMPAIGN,  ILLINOIS. 

The  bulletins  of    the  Experiment  Station  will  be  sent  free  of  all 
charges  to  persons  engaged  in  farming  who  may  request  that  they  be  sent. 

SELIM  H.  PEABODY, 

President  Board  of  Direction. 


i  Ci    n  f:- r'~'-^. 

mi 


,  ^^^->;:^ '.-  X| 


*  ^dli'  -  -    :        > 

3*£l  ~y^  -y^- 

^^  -  .-.  v     .^^^_ V  ''^T .         *^~- 


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